in win8, I right click on a button at the taskbar (that represents opened windows) and the resulting context menu, immediately animates and goes to the top of the screen, without leaving visible the 'close' button! and it appears less than it's full size!
this is a major annoyance that existed since I bought the pc with installed win8
Try creating a new account, see if the problem exists there or not. If not you can copy everything from the old, corrupted account to the new one. Test for awhile then delete the old one along with it's files.
Says it's for Windows 7 but also works for Windows 8.
Note: Before you can copy anything, you must first logon with the new profile by logging off the current one and logging on with the new one or using Fast User Switching to logon to the new one without logging off of the old one.